MSG is a flavor enhancer used in many of the packaged and processed foods we eat. It is the sodium salt of glutamic acid, which is in a class of chemicals known as excitotoxins. High levels of excitotoxins have been shown in animal studies to cause damage to certain areas of the brain.

Scientists disagree as to just how dangerous excitotoxins are to humans. Some feel that humans are not as susceptible to excitotoxins as rodents, therefore we should not be concerned about using them as a food additive. Other scientists believe that humans are 5-6 times more susceptible because humans concentrate excitotoxins in the blood more than other animals.

Study Design and Results

In the first phase of this study, 57 FM patients who also had irritable bowel syndrome (IBS) were placed on a four-week diet that excluded dietary additive excitotoxins including MSG and aspartame. Of the 37 who completed the diet, 84% reported that over 30% of their symptoms had resolved.

Participants who improved on the diet were then divided into two groups, with one group using MSG and the other group using a placebo for three consecutive days each week for two weeks; then the groups were switched for another two weeks.

The results showed that when participants were using MSG, they experienced:

A worsening of fibromyalgia severity.

Decreased quality of life in regards to IBS symptoms.

A non-significant trend toward worsening FM pain.

The researchers concluded that "dietary glutamate may be contributing to FM symptoms in some patients."

My Thoughts…

I knew that some people have a severe reaction to MSG but beyond that, I was not aware that it could also be dangerous for those of us who don’t exhibit such a clear negative response. Nor did I realize that it could make FM symptoms worse.

While it will take more and larger studies to determine what percentage of FM patients may be negatively affected by MSG, these findings are convincing enough that I’m going to start reading labels more carefully and try to eliminate MSG from my diet. It can’t hurt and hopefully it will help.